Solid electrolytic capacitors comprising electroconductive polymer as solid electrolyte, which can reduce equivalent series resistance and leakage current, are useful as capacitors satisfying needs for higher performance and downsizing of electronic devices, as compared with those solid electrolytic capacitors comprising manganese dioxide or the like as solid electrolyte. A solid electrolytic capacitor having a predetermined capacitance can be obtained by laminating solid electrolytic capacitor elements (elementary elements). Generally, an elementary element for solid electrolytic capacitor is, as shown in FIG. 1, prepared by forming a dielectric oxide film layer (2) on an anode substrate (1) of etched metal foil having a large specific surface area, forming a solid semiconductor layer (4) (hereinafter, referred to as solid electrolyte) on the oxide film layer as counter cathode part, and preferably further forming a conductive layer such as conductive paste layer (not shown in Figures). The exposed portion of the anode substrate serves as anode part. Generally, in order to ensure segregation between cathode part and anode part, masking material (3) is provided.
Lamination can be carried out in various-manners. For example, as shown in FIG. 3, cathode parts of two or more elementary elements (20) for solid electrolytic capacitor, which elements each have an anode part and a cathode part, are laminated on a cathode terminal (from which cathode lead (7) is coming out), anode lead (6) is allowed to come out of the anode part via appropriate conductor (5), and the whole is completely encapsulated with epoxy resin (8) to be a capacitor part (9).
Conventionally, in such a laminate-type solid electrolytic capacitor, for the purpose of obtaining good electric properties by preventing incomplete sealing in applying encapsulation, it has been considered as preferable to stack capacitor elements exactly one on another, that is, a structure including no portion of the elements out of alignment has been preferred (see Japanese Patent Application Laid Open No. H10-144573).
[Patent Document 1] Japanese Patent Application Laid Open No. H10-144573